The CTS-V is probably my favourite high-performance four-door on Earth. If you like the Corvette Z06 and its 6.2-litre, 650-hp V8 widow-maker, the CTS-V has the same power plant, just tuned down by 10 horses, to 640. You would be hard-pressed to notice the drop in power. In both the Caddy and Vette, you are getting extreme performance at a cost that is difficult to overlook.

Let us call this comparison a showdown between perhaps the greatest sedan in existence and the extreme value proposition. Read on to see who wins.

The CTS-V in “Red Obsession”. I enjoyed the vehicle immensely. Our test car cost over US$90,000 and was very well-optioned. The base cost of the CTS-V is about US$86,000.

The “V” cars are Caddy's answer to high-performance versions of European sports sedans: BMW’s M Sports, Mercedes-AMGs and the Audi RS. And, of course, dedicated high-end rides such as the Panamera.

It is tough to climb much higher in the General Motors line-up than the CTS-V, however. With the Z06 and forthcoming ZR1 ‘Vettes, you get mountains of power but no back seats, and the flagship CT6 Caddy does not yet come in V trim.

I will acknowledge that one might not be cross-shopping a CTS-V and a Panamera Turbo. But, a lot of folks do not think they should cross-shop a Z06 and, say, a Ferrari 488. That does not mean they should not.

I recently checked out the car in a fetching “Crystal White” paint job. It got some serious stares, but I still liked the CTS-V better in red.

The heart of the Caddy is the savage, 640-hp, supercharged V8 LT4 motor, which the CTS-V shares with the Corvette Z06.

This engine is sublime. For my money, it is better than the Porsche’s 550-hp V8, but I think that big V8s get along better with superchargers than turbochargers. (Both increase the compression of airflow headed in an engine’s cylinders for combustion, but superchargers are powered by the motor, whereas turbos are spun by engine exhaust.)

The best part of driving a CTS-V, in many ways, is starting it up and hearing the gutsy roar and rumble. Because we are dealing with a luxury sedan, out on the road, the CTS-V isolated the driver and passengers from the exhaust note, but you can sure feel those 640 horses doing their thing.

The eight-speed automatic has a manual mode, so you can use the paddles behind the steering wheel to shift your gears. The CTS-V also has various drive modes, including a ferocious “track” option. I found that skipping the paddles and going with “comfort” and “sport” modes were the best route.

“Driving the car is glorious,” I wrote in 2016. “The Z06 requires constant attention ... The CTS-V, by contrast, is an insane beast when you want it to be, possessed of earth-splitting violence delivered via a 0-to-60mph time of 3.6 seconds.”

Cadillac Cue has become one of the best and most user-friendly infotainment set-ups available.

The large touch screen is responsive, the Bose audio system sounds wonderful, and there is easy Bluetooth connectivity, Apple CarPlay, Android Auto and 4G LTE Wi-fi.

There is a reason this GM system was a runner-up for our Infotainment System of the Year in 2016. But what about the driving?

“Cadillac has been working on taking it to BMW’s M cars for some time now, and with the CTS-V ... well, it may have taken it past the M’s,” I wrote in my 2016 review.

“The CTS-V bears no resemblance to the Caddys of the Carter and Reagan administrations, and it has grabbed the sports-sedan concept and pushed it into new territory. You can now have your midlife crisis without embarrassing yourself.”

Now that I have checked back in with the car, how does it stack up against the Panamera? Let’s find out.

The Panamera Turbo, in all its glory, was our 2017 Car of the Year.

Here is what BI’s Ben Zhang had to say in his review

“The new second-generation Porsche Panamera is an absolute gem of a car. The combination of old-school driving pleasure, state-of-the-art tech, and refined luxury make it a compelling option for anyone looking for a vehicle in this genre.

“Even with a new chassis and electronics, the new Panamera is more evolutionary than revolutionary ... But with the makeover, the Panamera now has the matinee-idol looks to go with its world-class ability. And with this, Porsche has created the finest sports sedan in the world. It’s certainly not cheap, but boy is it good. If you are one of the blessed few who can afford a new Porsche Panamera, don’t think – just do it. Your life will be better for it.”

That is 100 fewer ponies than the Caddy — but it does not feel like it. The Panamera Turbo exudes power with every stomp of the gas pedal.

The 0-60 time has been clocked at 3.4 seconds, meaning the Panamera and the CTS-V are in a near dead heat on the drag strip. In the old days, you might have concluded that the performance comparisons would end once the cars have to go around corners and cannot just duel in a straight line.

But the Caddy produces a lighter vibe when your hands are on the wheel and your eyes are seeking curves in the road. And guess what? The CTS-V weighs about 300 pounds (136kg) less than the Panamera (4,150 versus 4,400).

For me, the Panamera Turbo had a solid, planted demeanour – and this bummed me out a bit. I wanted a little more Porsche sportiness.

The CTS-V, by contrast, had that wild vibe. Quite rewarding. The Panamera 4S – with its smaller, 440-hp turbo six-banger – gave me more of what I was looking for. But our competition here is between the CTS-V and the Panamera Turbo.

Some of the extra weight and ground-grabbing of the Porsche can be chalked up to all-wheel-drive. Both cars are running eight-speed automatic transmissions – the Porsche a dual-clutch unit with marvellous paddle shifters, the Caddy an automatic-manual option that I did not seem to want to use that much. Keeping it in sport mode and letting the CTS-V do its own shifting was fine.

Porsche’s infotainment system is much improved.

“The PCM system is a major leap forward for the German sports-car maker,” we wrote in our selection of the Panamera as our 2017 Car of the Year. “It marks a major improvement in capability and usability over the previous infotainment system.”

We added: “Overall, the Panamera's new infotainment system is a success. It's quick, responsive, and packed with features. But the system is complicated to use. It’s an unfortunate by-product of Porsche trying to deliver so much functionality in such a small amount of real estate.”

All the critical features you would expect are present, however. There is nothing Cadillac Cue can do that the PCM cannot.

So how is the Panamera Turbo to drive?

I prefer the big Turbo’s little brother, the V6-powered 4S, but there is no denying that the Turbo is a tough-to-match combination of boulevard cruiser and spirited sports sedan. You might think this would mean the car has a dual-personality problem: a limo masquerading as a sports car, or vice versa.